Monitoring of blood glucose concentration is, for diabetics, an essential part of their daily routine. The blood glucose concentration has to be determined quickly and easily, and several times a day, to determine suitable medical steps. To ensure that the diabetic's daily routine is impinged on no more than is necessary, suitable portable appliances are often used so that the blood glucose can be measured at the workplace during leisure time.
Various portable appliances are presently available on the market, some of them functioning according to different measurement methods. For example optical or electro-chemical measurement methods are used in such diagnostic devices. One example of a frequently employed measurement method uses a special kind of electrochemical test strips. These test strips are designed in such a way that a predefined amount of blood is guided via a capillary system to an electrode system. For modem test strips, a blood quantity of ca. 1.5 microliters is sufficient, in some cases even quantities of blood of less than one miroliter. The electrode system can, for example, involve gold electrodes which are provided with a coating. The coating in most cases contains various enzymes and so-called mediators and has the effect that charge carriers (for example in the form of redox molecules) form within the sample on the electrodes, the concentration of these charge carriers being dependent on the blood glucose concentration. The concentration of these charge carriers can be determined by means of the gold electrodes and a suitable measurement system known to the skilled person, for example by means of a comparatively simple current-voltage measurement, and thus calculated back to the blood glucose concentration.
An important element of portable diagnostic systems of this kind is thus represented by the corresponding test strips and by the systems for output of these test strips. About 5 to 7 such test strips are typically needed each day by a diabetic. It is imperative that the test strips are kept clean and dry in order to ensure that the measurement of the blood glucose concentration is not rendered false by corresponding soiling or by the action of moisture.
Prior art systems are known with means for storing and outputting of test strips. The device described essentially comprises an arrangement which is moisture-tight and air-tight and in which corresponding test strips are stored and can be output by means of a slide device. However, prior art devices do not contain any means for diagnosis, i.e. for measuring the blood glucose concentration for example. Moreover, the described device does not include any means for preparing suitable samples, for example a lancet system for obtaining drops of blood. Therefore, the device described in EP 1 321 769 A1 can be used only in combination with suitable lancet systems and diagnostic systems for evaluation of the test strips.
A device for storing and outputting of test strips is also disclosed in WO 02/055008 A2. In the latter, a test strip cassette is stored in a tube which is in turn accommodated in a housing. The housing has a button and mechanism by means of which a test strip can be output from the tube. WO 02/055008 too does not describe a complete diagnostic system, but only a suitable output unit for test strips, which unit can be used only in combination with other systems, in particular with a lancet system and a diagnostic or measurement system. This greatly increases the space taken up by the devices required for routine monitoring of blood glucose concentrations.
WO 03/083469 A2 discloses an integrated test appliance which, for example, can be used for electrochemical or photometric analysis of a blood sample. The integrated measurement system encloses a lancet system, a sensor and a test strip cartridge within a single housing. However, the system described in WO 03/083469 A2 has a number of disadvantages affecting its everyday use. In particular, the system described is a one-piece system in which all the components are integrated in one housing. As a result, the described system takes up a great deal of space and is heavy. Moreover, in the system described, separate tensioning of the integrated lancet system is required. Nor does the system described in WO 03/083469 A2 solve the problem often arising in blood glucose concentration measurements, namely that the properties of the test strips used may vary from batch to batch. This results in sometimes huge variations in the accuracy of the blood glucose concentration measurement. Furthermore, the system described in WO 03/083469 A2 has the disadvantage that an additional test strip cartridge is necessary, test strips. The space taken up by the described system is further increased by this “double housing”.